The development of automated fluorescent methods has led to increased data generation in DNA sequencing projects. Smith et al U.S. Pat. No. 5,171,534 have described a fluorescent DNA sequencing system. Waggoner et al U.S. Pat. No. 5,268,486 have described the properties of some conjugates of cyanine dyes and Middendorf U.S. Pat. No. 5,230,781 and Patonay EP 670 374 have described the use of various cyanine dyes in DNA sequencing. Berger et al European patent 214 847 has described the use of other cyanine dyes some of which contain squarate groups in assays which involve a specific binding partner. Other squarate dyes are described by Pease et al in U.S. Pat. No. 4,830,786 and subsequent divisional patents, and by A J G Mank et al in Anal. Chem. 1995, 67, 1742-8. Cushman et al WO 93/09172 and Krutak et al WO94/19387 have described cyanine dyes containing squarate groups for use in thermoplastics and inks.
There is a need for methods of detecting biologically significant chemical species (hereafter biological molecules) at increased convenience and sensitivity in general and particularly for DNA sequencing and DNA mapping experiments.